Recent studies have found a significant increase in the incidence of Type 2 or non insulin-dependent diabetes mellitus (NIDDM) among individuals equal to or younger than 19 years of age. The increase in Type 2 diabetes in children is of concern and could represent the early onset of what is commonly thought to be a disease of older adults. Because obesity and insulin resistance (both prime factors in Type 2 diabetes) are associated with specific birth cohorts, the intrauterine environment appears to play a central role in predisposing individuals to the development of Type 2 diabetes but the cause(s) of this increase are not well understood. Ongoing research has suggested that serum and/or tissue fatty acids play a major role in determining insulin responsiveness and both acute and chronic studies have shown that high dietary fat (triglyceride) intake suppress the ability of tissues to take up glucose. Furthermore, the maternal diet during pregnancy can have profound, long-term effects on the offspring, including suppression of the offspring's insulin responsiveness. In addition, the maternal diet prior to and during pregnancy can have unfavorable effects on the mother and on the outcome of the pregnancy, especially if the mother's diet is high in fat. Maternal tissue fatty acid levels and high dietary fat intake are both correlated with the development of gestational diabetes mellitus (GDM) and women who developed GDM have been found to have higher serum fatty acid levels prior to conception. The occurrence of GDM during a second pregnancy was also much more likely if the subsequent pre-conception maternal diet contained high levels of fat. Studies are proposed using a rat model to examine the effect of maternal dietary fat levels on the mother and on her offspring. Using fat levels commonly found in the American diet, experiments are proposed to examine the relationship between maternal fat intake, maternal and offspring serum and tissue fatty acid (FA) levels and the in vitro and in vivo insulin sensitivity of the mother and the offspring.